Patent GB-1501614-A (GB)
Title: Method of internal lining and sealing of buried pipeline
IPC: F16L55/165
Filed: 1974-01-21
Abstract: 1501614 Lining pipes L A R ROSS 20 Jan 1975 [21 Jan 1974 4 Sept 1974] 02824/74 and 38688/74 Heading F2P A method of lining a buried pipeline with a flexible imperforate lining tube comprises the steps of introducing the lining tube into the pipeline in a collapsed state, sealing the ends of the lining tube circumferentially to the ends of the pipeline; exhausting the space between the lining tube and the inside walls of the pipeline and allowing the lining tube to inflate by progressive admission of air into the lining tube at one end of the pipeline whilst exhaustion of the space is continued at the other end. A lining tube 25, in a flattened state, is dispensed from a reel 41 supported on a frame 40 and an underlay 26, in the form of a strip or flattened tube, is dispensed from a reel 42. The underlay and lining tube are towed through an adhesive applicator 14 into a gas main 16 by a towing carriage 15 situated in the main and towed by a winch cable 36. The adhesive applicator applies a layer of adhesive to the upper surface of the lining tube and when said lining tube is installed within the main 16, its ends are sealed to the respective ends of the main and the lining tube is then inflated to contact and adhere to the upper inner surface of the main. The underlay may be withdrawn or left in place. Alternatively by suitable application of adhesive to the lining tube and/or the main, the lining tube may be adhered to the entire inner surface of the main. The adhesive applicator 14 comprises a tray 17 which is semi-cylindrically shaped at one end to locate in the end of the gas main 16 where it is fixed by brackets 18 and screws 19. A roller 21 controls the thickness of the layer of adhesive 24 which is applied to the lining tube. The adhesive may be an epoxy or polyester resin and may contain a filler such as marble dust. Adhesive suitably employing a natural or synthetic rubber may also be applied, for example by spraying, to the inside wall of the main. The towing carriage 15 comprises two sets of wheels 29, a towing plate 34 pivotally connected to a bracket 31 and having a semi-cylindrical crosssection at one end where the lining tube and underlay are attached by clamps 35, a central shaft 27 which rotatably supports bosses 39 to which the wheels are connected and a weight 30 to ensure that the U-shaped bracket 31 remains in a substantially vertical plane. A unit (Fig. 9) which may be employed in inflating the lining tube comprises two metal discs 48, 49 held together by a bolt which when tightened causes a rubber ring 47 to expand and engage a rubber ring 46 holding the end of the lining tube 25. Attached to the disc 49 is a rubber, plastics or metal core 50 having ducts 53, 54 and 55. The lining tube and the space between the lining tube and the wall of the main are evacuated and then air is admitted to the inside of the lining tube to inflate it into contact with the inside wall of the main. One or more lining tubes may be installed in the main and a hard setting adhesive used with or without foam-like plastics, to form a rigid lining.